Loading...
Note: File does not exist in v3.1.
1/*
2 * Copyright (C) 2012 Google, Inc.
3 *
4 * This software is licensed under the terms of the GNU General Public
5 * License version 2, as published by the Free Software Foundation, and
6 * may be copied, distributed, and modified under those terms.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 */
14
15#include <linux/device.h>
16#include <linux/err.h>
17#include <linux/errno.h>
18#include <linux/kernel.h>
19#include <linux/init.h>
20#include <linux/io.h>
21#include <linux/list.h>
22#include <linux/memblock.h>
23#include <linux/rslib.h>
24#include <linux/slab.h>
25#include <linux/vmalloc.h>
26#include <linux/pstore_ram.h>
27#include <asm/page.h>
28
29struct persistent_ram_buffer {
30 uint32_t sig;
31 atomic_t start;
32 atomic_t size;
33 uint8_t data[0];
34};
35
36#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
37
38static inline size_t buffer_size(struct persistent_ram_zone *prz)
39{
40 return atomic_read(&prz->buffer->size);
41}
42
43static inline size_t buffer_start(struct persistent_ram_zone *prz)
44{
45 return atomic_read(&prz->buffer->start);
46}
47
48/* increase and wrap the start pointer, returning the old value */
49static size_t buffer_start_add_atomic(struct persistent_ram_zone *prz, size_t a)
50{
51 int old;
52 int new;
53
54 do {
55 old = atomic_read(&prz->buffer->start);
56 new = old + a;
57 while (unlikely(new >= prz->buffer_size))
58 new -= prz->buffer_size;
59 } while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
60
61 return old;
62}
63
64/* increase the size counter until it hits the max size */
65static void buffer_size_add_atomic(struct persistent_ram_zone *prz, size_t a)
66{
67 size_t old;
68 size_t new;
69
70 if (atomic_read(&prz->buffer->size) == prz->buffer_size)
71 return;
72
73 do {
74 old = atomic_read(&prz->buffer->size);
75 new = old + a;
76 if (new > prz->buffer_size)
77 new = prz->buffer_size;
78 } while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
79}
80
81static DEFINE_RAW_SPINLOCK(buffer_lock);
82
83/* increase and wrap the start pointer, returning the old value */
84static size_t buffer_start_add_locked(struct persistent_ram_zone *prz, size_t a)
85{
86 int old;
87 int new;
88 unsigned long flags;
89
90 raw_spin_lock_irqsave(&buffer_lock, flags);
91
92 old = atomic_read(&prz->buffer->start);
93 new = old + a;
94 while (unlikely(new >= prz->buffer_size))
95 new -= prz->buffer_size;
96 atomic_set(&prz->buffer->start, new);
97
98 raw_spin_unlock_irqrestore(&buffer_lock, flags);
99
100 return old;
101}
102
103/* increase the size counter until it hits the max size */
104static void buffer_size_add_locked(struct persistent_ram_zone *prz, size_t a)
105{
106 size_t old;
107 size_t new;
108 unsigned long flags;
109
110 raw_spin_lock_irqsave(&buffer_lock, flags);
111
112 old = atomic_read(&prz->buffer->size);
113 if (old == prz->buffer_size)
114 goto exit;
115
116 new = old + a;
117 if (new > prz->buffer_size)
118 new = prz->buffer_size;
119 atomic_set(&prz->buffer->size, new);
120
121exit:
122 raw_spin_unlock_irqrestore(&buffer_lock, flags);
123}
124
125static size_t (*buffer_start_add)(struct persistent_ram_zone *, size_t) = buffer_start_add_atomic;
126static void (*buffer_size_add)(struct persistent_ram_zone *, size_t) = buffer_size_add_atomic;
127
128static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
129 uint8_t *data, size_t len, uint8_t *ecc)
130{
131 int i;
132 uint16_t par[prz->ecc_info.ecc_size];
133
134 /* Initialize the parity buffer */
135 memset(par, 0, sizeof(par));
136 encode_rs8(prz->rs_decoder, data, len, par, 0);
137 for (i = 0; i < prz->ecc_info.ecc_size; i++)
138 ecc[i] = par[i];
139}
140
141static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
142 void *data, size_t len, uint8_t *ecc)
143{
144 int i;
145 uint16_t par[prz->ecc_info.ecc_size];
146
147 for (i = 0; i < prz->ecc_info.ecc_size; i++)
148 par[i] = ecc[i];
149 return decode_rs8(prz->rs_decoder, data, par, len,
150 NULL, 0, NULL, 0, NULL);
151}
152
153static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
154 unsigned int start, unsigned int count)
155{
156 struct persistent_ram_buffer *buffer = prz->buffer;
157 uint8_t *buffer_end = buffer->data + prz->buffer_size;
158 uint8_t *block;
159 uint8_t *par;
160 int ecc_block_size = prz->ecc_info.block_size;
161 int ecc_size = prz->ecc_info.ecc_size;
162 int size = ecc_block_size;
163
164 if (!ecc_size)
165 return;
166
167 block = buffer->data + (start & ~(ecc_block_size - 1));
168 par = prz->par_buffer + (start / ecc_block_size) * ecc_size;
169
170 do {
171 if (block + ecc_block_size > buffer_end)
172 size = buffer_end - block;
173 persistent_ram_encode_rs8(prz, block, size, par);
174 block += ecc_block_size;
175 par += ecc_size;
176 } while (block < buffer->data + start + count);
177}
178
179static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
180{
181 struct persistent_ram_buffer *buffer = prz->buffer;
182
183 if (!prz->ecc_info.ecc_size)
184 return;
185
186 persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
187 prz->par_header);
188}
189
190static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
191{
192 struct persistent_ram_buffer *buffer = prz->buffer;
193 uint8_t *block;
194 uint8_t *par;
195
196 if (!prz->ecc_info.ecc_size)
197 return;
198
199 block = buffer->data;
200 par = prz->par_buffer;
201 while (block < buffer->data + buffer_size(prz)) {
202 int numerr;
203 int size = prz->ecc_info.block_size;
204 if (block + size > buffer->data + prz->buffer_size)
205 size = buffer->data + prz->buffer_size - block;
206 numerr = persistent_ram_decode_rs8(prz, block, size, par);
207 if (numerr > 0) {
208 pr_devel("persistent_ram: error in block %p, %d\n",
209 block, numerr);
210 prz->corrected_bytes += numerr;
211 } else if (numerr < 0) {
212 pr_devel("persistent_ram: uncorrectable error in block %p\n",
213 block);
214 prz->bad_blocks++;
215 }
216 block += prz->ecc_info.block_size;
217 par += prz->ecc_info.ecc_size;
218 }
219}
220
221static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
222 struct persistent_ram_ecc_info *ecc_info)
223{
224 int numerr;
225 struct persistent_ram_buffer *buffer = prz->buffer;
226 int ecc_blocks;
227 size_t ecc_total;
228
229 if (!ecc_info || !ecc_info->ecc_size)
230 return 0;
231
232 prz->ecc_info.block_size = ecc_info->block_size ?: 128;
233 prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;
234 prz->ecc_info.symsize = ecc_info->symsize ?: 8;
235 prz->ecc_info.poly = ecc_info->poly ?: 0x11d;
236
237 ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,
238 prz->ecc_info.block_size +
239 prz->ecc_info.ecc_size);
240 ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;
241 if (ecc_total >= prz->buffer_size) {
242 pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
243 __func__, prz->ecc_info.ecc_size,
244 ecc_total, prz->buffer_size);
245 return -EINVAL;
246 }
247
248 prz->buffer_size -= ecc_total;
249 prz->par_buffer = buffer->data + prz->buffer_size;
250 prz->par_header = prz->par_buffer +
251 ecc_blocks * prz->ecc_info.ecc_size;
252
253 /*
254 * first consecutive root is 0
255 * primitive element to generate roots = 1
256 */
257 prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
258 0, 1, prz->ecc_info.ecc_size);
259 if (prz->rs_decoder == NULL) {
260 pr_info("persistent_ram: init_rs failed\n");
261 return -EINVAL;
262 }
263
264 prz->corrected_bytes = 0;
265 prz->bad_blocks = 0;
266
267 numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
268 prz->par_header);
269 if (numerr > 0) {
270 pr_info("persistent_ram: error in header, %d\n", numerr);
271 prz->corrected_bytes += numerr;
272 } else if (numerr < 0) {
273 pr_info("persistent_ram: uncorrectable error in header\n");
274 prz->bad_blocks++;
275 }
276
277 return 0;
278}
279
280ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
281 char *str, size_t len)
282{
283 ssize_t ret;
284
285 if (!prz->ecc_info.ecc_size)
286 return 0;
287
288 if (prz->corrected_bytes || prz->bad_blocks)
289 ret = snprintf(str, len, ""
290 "\n%d Corrected bytes, %d unrecoverable blocks\n",
291 prz->corrected_bytes, prz->bad_blocks);
292 else
293 ret = snprintf(str, len, "\nNo errors detected\n");
294
295 return ret;
296}
297
298static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
299 const void *s, unsigned int start, unsigned int count)
300{
301 struct persistent_ram_buffer *buffer = prz->buffer;
302 memcpy(buffer->data + start, s, count);
303 persistent_ram_update_ecc(prz, start, count);
304}
305
306void persistent_ram_save_old(struct persistent_ram_zone *prz)
307{
308 struct persistent_ram_buffer *buffer = prz->buffer;
309 size_t size = buffer_size(prz);
310 size_t start = buffer_start(prz);
311
312 if (!size)
313 return;
314
315 if (!prz->old_log) {
316 persistent_ram_ecc_old(prz);
317 prz->old_log = kmalloc(size, GFP_KERNEL);
318 }
319 if (!prz->old_log) {
320 pr_err("persistent_ram: failed to allocate buffer\n");
321 return;
322 }
323
324 prz->old_log_size = size;
325 memcpy(prz->old_log, &buffer->data[start], size - start);
326 memcpy(prz->old_log + size - start, &buffer->data[0], start);
327}
328
329int notrace persistent_ram_write(struct persistent_ram_zone *prz,
330 const void *s, unsigned int count)
331{
332 int rem;
333 int c = count;
334 size_t start;
335
336 if (unlikely(c > prz->buffer_size)) {
337 s += c - prz->buffer_size;
338 c = prz->buffer_size;
339 }
340
341 buffer_size_add(prz, c);
342
343 start = buffer_start_add(prz, c);
344
345 rem = prz->buffer_size - start;
346 if (unlikely(rem < c)) {
347 persistent_ram_update(prz, s, start, rem);
348 s += rem;
349 c -= rem;
350 start = 0;
351 }
352 persistent_ram_update(prz, s, start, c);
353
354 persistent_ram_update_header_ecc(prz);
355
356 return count;
357}
358
359size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
360{
361 return prz->old_log_size;
362}
363
364void *persistent_ram_old(struct persistent_ram_zone *prz)
365{
366 return prz->old_log;
367}
368
369void persistent_ram_free_old(struct persistent_ram_zone *prz)
370{
371 kfree(prz->old_log);
372 prz->old_log = NULL;
373 prz->old_log_size = 0;
374}
375
376void persistent_ram_zap(struct persistent_ram_zone *prz)
377{
378 atomic_set(&prz->buffer->start, 0);
379 atomic_set(&prz->buffer->size, 0);
380 persistent_ram_update_header_ecc(prz);
381}
382
383static void *persistent_ram_vmap(phys_addr_t start, size_t size)
384{
385 struct page **pages;
386 phys_addr_t page_start;
387 unsigned int page_count;
388 pgprot_t prot;
389 unsigned int i;
390 void *vaddr;
391
392 page_start = start - offset_in_page(start);
393 page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
394
395 prot = pgprot_noncached(PAGE_KERNEL);
396
397 pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL);
398 if (!pages) {
399 pr_err("%s: Failed to allocate array for %u pages\n", __func__,
400 page_count);
401 return NULL;
402 }
403
404 for (i = 0; i < page_count; i++) {
405 phys_addr_t addr = page_start + i * PAGE_SIZE;
406 pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
407 }
408 vaddr = vmap(pages, page_count, VM_MAP, prot);
409 kfree(pages);
410
411 return vaddr;
412}
413
414static void *persistent_ram_iomap(phys_addr_t start, size_t size)
415{
416 if (!request_mem_region(start, size, "persistent_ram")) {
417 pr_err("request mem region (0x%llx@0x%llx) failed\n",
418 (unsigned long long)size, (unsigned long long)start);
419 return NULL;
420 }
421
422 buffer_start_add = buffer_start_add_locked;
423 buffer_size_add = buffer_size_add_locked;
424
425 return ioremap(start, size);
426}
427
428static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
429 struct persistent_ram_zone *prz)
430{
431 prz->paddr = start;
432 prz->size = size;
433
434 if (pfn_valid(start >> PAGE_SHIFT))
435 prz->vaddr = persistent_ram_vmap(start, size);
436 else
437 prz->vaddr = persistent_ram_iomap(start, size);
438
439 if (!prz->vaddr) {
440 pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
441 (unsigned long long)size, (unsigned long long)start);
442 return -ENOMEM;
443 }
444
445 prz->buffer = prz->vaddr + offset_in_page(start);
446 prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
447
448 return 0;
449}
450
451static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
452 struct persistent_ram_ecc_info *ecc_info)
453{
454 int ret;
455
456 ret = persistent_ram_init_ecc(prz, ecc_info);
457 if (ret)
458 return ret;
459
460 sig ^= PERSISTENT_RAM_SIG;
461
462 if (prz->buffer->sig == sig) {
463 if (buffer_size(prz) > prz->buffer_size ||
464 buffer_start(prz) > buffer_size(prz))
465 pr_info("persistent_ram: found existing invalid buffer,"
466 " size %zu, start %zu\n",
467 buffer_size(prz), buffer_start(prz));
468 else {
469 pr_debug("persistent_ram: found existing buffer,"
470 " size %zu, start %zu\n",
471 buffer_size(prz), buffer_start(prz));
472 persistent_ram_save_old(prz);
473 return 0;
474 }
475 } else {
476 pr_debug("persistent_ram: no valid data in buffer"
477 " (sig = 0x%08x)\n", prz->buffer->sig);
478 }
479
480 prz->buffer->sig = sig;
481 persistent_ram_zap(prz);
482
483 return 0;
484}
485
486void persistent_ram_free(struct persistent_ram_zone *prz)
487{
488 if (!prz)
489 return;
490
491 if (prz->vaddr) {
492 if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
493 vunmap(prz->vaddr);
494 } else {
495 iounmap(prz->vaddr);
496 release_mem_region(prz->paddr, prz->size);
497 }
498 prz->vaddr = NULL;
499 }
500 persistent_ram_free_old(prz);
501 kfree(prz);
502}
503
504struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
505 u32 sig, struct persistent_ram_ecc_info *ecc_info)
506{
507 struct persistent_ram_zone *prz;
508 int ret = -ENOMEM;
509
510 prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
511 if (!prz) {
512 pr_err("persistent_ram: failed to allocate persistent ram zone\n");
513 goto err;
514 }
515
516 ret = persistent_ram_buffer_map(start, size, prz);
517 if (ret)
518 goto err;
519
520 ret = persistent_ram_post_init(prz, sig, ecc_info);
521 if (ret)
522 goto err;
523
524 return prz;
525err:
526 persistent_ram_free(prz);
527 return ERR_PTR(ret);
528}